Various diners, restaurants and highway rest areas are using a billboard light emitting device with a billboard so as to advertise or promote the menu of various foods. The billboard light emitting device 1′, as shown in FIG. 7, a lighting part 27′ formed of one or multiple fluorescent lamp or common electric bulb in the interior of an engaging frame 2′ formed in a rectangular shape, and a transparent billboard 26′ on which is printed an image, a text, a graphic, a photo, etc. sowing various menu is provided on a front side, and the billboard 26′ emits light from the lighting part 27′ formed of a fluorescent lamp or a common electric bulb, so it can be easily recognized at day and night. The above mentioned light emitting device 1′ is generally mounted on a front side of one billboard 26′. The diner or the restaurant where needs to advertise or promote using multiple photos and images on various foods tend to install multiple billboard light emitting devices 1′ for the purpose of advertising or promoting various menu at a time, so that the user can easily select a certain menu from the multiple billboards 26′.
However the above mentioned conventional light emitting device 1′ necessitates a plurality of light emitting devices 1′ so as to advertise and promote various menu, and one billboard 26′ is installed at each light emitting device 1′, so the installation is hard, and a power consumption rises owing to maintaining multiple light emitting devices 1′ at a time. If the size of the billboard 26′ is needed to be made longer or shorter due to the exchange of a new menu or existing menu, it necessitates a new installation of another size light emitting device 1′. In addition, the billboard 26′ of the front side is configured to emit light from the lighting part 27′ formed of fluorescent lamp or electric bulb, so a wider space for installing the fluorescent lamps or the electric bulb is needed, and the front and back wise width and size of the light emitting device 1′ are made larger, which makes it hard to install, and the visibility of the lighting part 27′ such as the fluorescent lamp or electric bulb is worse than the light emitting device using light emitting devices, and the service life is shorter, so it is needed to frequently exchange it.
In addition, the Korean utility model registration number 20-0396887 discloses a billboard comprising a frame the front side of which is open, and the upper and lower sides of which are bent, a plurality of light emitting diodes which are arranged in the longitudinal direction of the frame, a block frame installed on the frame, and a plurality of billboard blocks which are assembled to the block frame; however in the above conventional billboard, the frame does not have any section bar, which makes it impossible to form multiple spaces. It lacks a light guide plate having cut scanning lines. As the multiple billboard blocks fit in series in the frame, the multiple billboard blocks with engraved billboard texts are configured to combine one advertisement text. In the above mentioned construction, the old billboard blocks are needed to be removed so as to form another advertisement text, and then the billboard blocks with engraved advertisement texts are reinstalled. So, the installation and assembling procedures grow complicated, and the exchange cost of the billboard blocks rises greatly.